Environmental enrichment has no effect on the development of dopaminergic and GABAergic fibers during methylphenidate treatment of early traumatized gerbils

Susanne Brummelte¹^,3 , Thorsten Grund¹ , Gunther H Moll² , Gertraud Teuchert-Noodt¹ and Ralph R Dawirs²

¹Department of Neuroanatomy/Cognitive Neuroscience, Faculty of Biology, University of Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany

²Department of Child and Adolescent Psychiatry, University Hospital Erlangen, Schwabachanlage 6 + 10, D-91054 Erlangen, Germany

³Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, V6T 1Z4, Canada

author email corresponding author email

Journal of Negative Results in BioMedicine 2008, 7:2doi:10.1186/1477-5751-7-2


Published:	16 May 2008

Abstract

It is widely believed, that environmental factors play a crucial role in the etiology and outcome of psychiatric diseases such as Attention-Deficit/Hyperactivity Disorder (ADHD). A former study from our laboratory has shown that both methylphenidate (MP) and handling have a positive effect on the dopaminergic fiber density in the prefrontal cortex (PFC) of early traumatized gerbils (Meriones unguiculatus). The current study was performed to investigate if enriched environment during MP application has an additional influence on the dopaminergic and GABAergic fiber densities in the PFC and amygdala in this animal model.

Animals received a single early dose of methamphetamine (MA; 50 mg/kg; i.p.) on postnatal day (PD) 14, which is known to cause multiple changes in the subsequent development of several neurotransmitter systems including the dopaminergic systems, and were then treated with oral daily applications of MP (5 mg/kg) from PD30–60. Animals treated this way were either transferred to an enriched environment after weaning (on PD30) or were kept under impoverished rearing conditions.

There was no effect of an enriched environment on the dopaminergic or GABAergic fiber density neither in the PFC nor in the amygdala. With regard to former studies these results underline the particular impact of MP in the treatment of ADHD.